From polarized optical absorption and emission spectra of the tris-mu -thiolato bridged [Cr2L3](ClO4)(2)Cl .H2O . MeOH (L = 2, 6-bis(aminomethyl)-4-tert-butyl-thiophenolate) 1 in the visible and near UV, the exchange splittings of the (4)A(2) ground and the E-2 and T-2(1) excited states are determined. In view of the large Cr-Cr distance of 3.01 Angstrom, the antiferromagnetic ground state splitting with J = 78 cm(-1) (H = J((SASB)-S-.)) is large compared to other triply bridged Cr3+ dimers. This can be rationalized using a model based on a valence bond approach, in which the exchange splittings are derived from configuration interactions between the ground electron configuration and ligand-to-metal (LMCT) as well as metal-to-metal (MMCT) charge-transfer configurations. Tt allows us to distinguish the interactions via ligand orbitals from the direct interactions between the metal-centered orbitals. We compare our results with those obtained for the tri-mu -hydroxo-bridged [Cr-2(OH)(3)(tmtame)(2)](NO3)(3) (tmtame = N,N ' ,N " -trimethyl-1,1,1-tris(aminomethyl)ethane) 2. In the latter the interactions via the Ligands are negligible, whereas they play an important role in 1, due to the softness of the sulfur ligand atoms.